Enhanced Piezoelectric Effect Derived from Grain Boundary in MoS₂ Monolayers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) layered materials exhibit piezoelectricity, crucial for flexible electronics.
• Current piezoelectricity in 2D materials is too weak for practical use.
• Molybdenum disulfide (MoS2) is a key 2D material with piezoelectric potential.

Purpose of the Study:

• To investigate the effect of grain boundaries (GBs) on the piezoelectric properties of monolayer MoS2.
• To explore the potential of GB-enhanced MoS2 in practical electronic devices.
• To develop self-powered sensors for health monitoring.

Main Methods:

• Fabrication of butterfly-shaped monolayer MoS2 structures.
• Characterization of piezoelectric properties influenced by grain boundaries.
• Development and testing of a flexible piezoelectric device.

Main Results:

• Grain boundaries in monolayer MoS2 significantly enhance piezoelectric output power by approximately 50%.
• GB-induced piezoelectric effect arises from deformable boundaries promoting polarization.
• The enhanced piezoelectricity shows direction-dependent coefficients.

Conclusions:

• Grain boundaries are a key factor in enhancing the piezoelectric performance of 2D materials like MoS2.
• GB-enhanced MoS2 is suitable for flexible piezoelectric devices.
• Demonstrated potential for self-powered precision sensors in human blood pressure monitoring.